<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>DOM元素节点遍历</title>
  </head>
  <body>
    <div>第一个DIV</div>
    <ul>
      <li>列表项1</li>
      <li>列表项2</li>
      <li>列表项3</li>
    </ul>
    <script>
      for (let elem of document.body.children) {
        console.log(elem);
      }
      console.log("第一个子元素节点");
      console.log(document.body.firstElementChild);
      console.log("最后一个子元素节点");
      console.log(document.body.lastElementChild);
      console.log("得到父节点");
      console.log(document.body.parentElement);
      console.log("前一个兄弟元素节点");
      console.log(document.body.children[1].previousElementSibling);
      console.log("后一个兄弟元素节点");
      console.log(document.body.children[1].nextElementSibling);

      console.log(document.body.children[1].children[1]);
    </script>
  </body>
</html>
